Light-emitting device and backlight including light-emitting device

ABSTRACT

The light-emitting device includes a first light-emitting element having an emission peak wavelength of 430 nm or more and less than 490 nm, a second light-emitting element having an emission peak wavelength of 490 nm or more and 570 nm or less, a support body at which the first light-emitting element and the second light-emitting element are disposed, and a light-transmissive member containing a red phosphor and covering the first light-emitting element and the second light-emitting element. A content density of the red phosphor in the light-transmissive member in a space between the first and second light-emitting elements is higher in a part below an upper surface of the second light-emitting element than in a part above the upper surface thereof.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This is a continuation application of U.S. patent application Ser. No.16/690,040, filed Nov. 20, 2019 which is a continuation application ofU.S. patent application Ser. No. 15/224,738, filed Aug. 1, 2016 andissued as U.S. Pat. No. 10,529,695 on Jan. 7, 2020, which claims thebenefit of Japanese Patent Application 2015-154045, filed on Aug. 4,2015, the entire disclosures of which are incorporated by referenceherein.

BACKGROUND OF THE INVENTION Field of the Invention

The present disclosure relates to a light-emitting device including alight-emitting element and a phosphor, and a backlight using thelight-emitting device.

Description of the Related Art

In general, light-emitting devices including light-emitting elements,such as a light-emitting diode (LED), are widely used as light sourcesfor various luminaires, including a backlight of a liquid crystaldisplay, a LED bulb, a LED fluorescent tube, and a ceiling light.

For example, a light-emitting device disclosed in JP 2007-158296 A andJP 2010-034183 A includes a red phosphor, a light-emitting element thatemits blue light, and another light-emitting element that emits greenlight. Such a light-emitting device achieves high color reproducibilitywhen used as the backlight of a liquid crystal display.

In the light-emitting device disclosed in each of JP 2007-158296 A andJP 2010-034183 A, for example, a plurality of light-emitting elements isplaced on the same support body, and among those light-emittingelements, the impact of light absorption might occur, as disclosed in WO2014/171394. Specifically, the light emitted from one light-emittingelement might be absorbed by another light-emitting element. As aresult, the luminous efficiency of the light-emitting device is reducedin some cases. For this reason, for the light-emitting device disclosedin WO 2014/171394, a wall is provided between the adjacentlight-emitting elements, disposed at the support body, to block theinvasion of light from other light-emitting elements, thereby preventingthe adverse effect of the light absorption among the light-emittingelements.

However, the light-emitting device disclosed in WO 2014/171394inevitably must form the wall between the adjacent light-emittingelements and therefore, it sometimes fails to meet the requirement forminiaturization.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present disclosure to provide alight-emitting device with excellent color reproducibility that can beeasily miniaturized.

A light-emitting device according to the present disclosure includes: afirst light-emitting element having an emission peak wavelength of 430nm or more and less than 490 nm; a second light-emitting element havingan emission peak wavelength of 490 nm or more and 570 nm or less; and alight-transmissive member containing a red phosphor and covering thefirst light-emitting element and the second light-emitting element, inwhich a content density of the red phosphor in the light-transmissivemember located in a space between the first and second light-emittingelements is higher in a part below an upper surface of the secondlight-emitting element than in a part above the upper surface thereof.

Therefore, the present disclosure can provide the light-emitting devicewith excellent color reproducibility that is easily miniaturized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic top view of a light-emitting device 100 accordingto a first embodiment.

FIG. 1B is a schematic cross-sectional view taken along the line Ib-Ibof FIG. 1A.

FIG. 2A is a schematic top view showing a light-emitting device 100A asa modified example of the light-emitting device 100.

FIG. 2B is a schematic cross-sectional view taken along the line IIb-IIbof FIG. 2A.

FIG. 3 is a schematic top view showing a backlight 200 according to asecond embodiment.

FIG. 4 is an emission spectrum of the light-emitting device 100 inExample 1.

FIG. 5 is an emission spectrum of a light-emitting device in ComparativeExample 1.

FIG. 6 shows a transmission spectrum of color filters used in Example 1.

FIG. 7 shows chromaticity coordinates in Example 1 and ComparativeExample 1.

FIG. 8 shows a transmission spectrum of color filters used in Example 2.

FIG. 9 shows chromaticity coordinates in Example 2 and ComparativeExample 2.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention will be described in detail belowwith reference to the accompanying drawings. Although in the descriptionbelow, terms indicative of specific directions and positions (e.g.,“upper”, “lower” and other terms including these words) will be used asneeded, they are used to make the present invention easier to understandwith reference to the drawings and not intended to restrict the scope ofthe present invention by their meanings. The same reference charactersrepresented through the drawings denote the same or equivalent parts ormembers.

The following embodiments are illustrative only to exemplify alight-emitting device for embodying the technical idea of the presentinvention, and the present invention is not limited thereto. The size,material, shape, relative arrangement, etc., of each component mentionedin the embodiments are not intended to limit the scope of the presentinvention thereto, unless otherwise specified, and are further intendedto exemplify the present invention. The size, positional relationship,and the like of members shown in some drawings are emphasized to makethe contents easily understood. Note that the relationship between acolor name and its chromaticity coordinates, the relationship betweenthe wavelength range of light and the color name of each single light,and the like are in conformity with JIS Z8110.

The light-emitting device according to the present disclosure includes,in addition to a first light-emitting element (blue light-emittingelement) having an emission peak wavelength of 430 nm or more and lessthan 490 nm, a second light-emitting element (green light-emittingelement) having an emission peak wavelength of 490 nm or more and 570 nmor less. The light-emitting device further includes a light-transmissivemember that contains a red phosphor and covers at least part of thefirst light-emitting element as well as at least part of the secondlight-emitting element.

In the light-transmissive member, the content density (distributiondensity) of a red phosphor in a space between the first light-emittingelement and the second light-emitting element is higher in a part belowan upper surface of the second light-emitting element than in a partabove the upper surface thereof.

Thus, the mutual absorption of light between the first and secondlight-emitting elements can be reduced without the necessity ofproviding any wall and the like therebetween.

The majority of light absorbed between the blue and green light-emittingelements is blue light emitted from the blue light-emitting element andpartly absorbed by a semiconductor of the green light-emitting element.Compared to this, the absorption of green light emitted from the greenlight-emitting element and absorbed by a semiconductor of the bluelight-emitting element is low.

Thus, the content density of the red phosphor in the light-transmissivemember is increased in the part below the upper surface of the greenlight in the space between the blue and green light-emitting elements,compared to that in the part above the upper surface thereof, wherebymost of the blue light directed to the green light-emitting element canbe converted into red light by means of the red phosphors, therebyreducing the absorption of blue light by the green light-emittingelement.

On the other hand, when the content density of the red phosphor isexcessively high across the entire light-transmissive member, the amountof blue light emitted from a light extraction surface of thelight-emitting device becomes small, while the amount of red lightbecomes excessive. For this reason, the content density (distributiondensity) of the red phosphor in the space between the first and secondlight-emitting elements is set lower in the part of thelight-transmissive member above the upper surface of the greenlight-emitting element. As a result, in the light-transmissive member,the content density (distribution density) of the red phosphor in thespace between the first and second light-emitting elements is set higherin the part below the upper surface of the second light-emitting elementthan in the part above the upper surface thereof.

The light-emitting device with this arrangement in the presentdisclosure can emit the green light and blue light having sharp peaksfrom the respective light emitting elements. Further, the absorption ofblue light by the green light-emitting element can be suppressed. Thus,the light-emitting device can achieve the excellent colorreproducibility and can be easily miniaturized, compared to aconventional light-emitting device.

The light-emitting devices according to the embodiments of the presentinvention will be described in detail below.

1. First Embodiment

FIG. 1A is a schematic top view of a light-emitting device 100 in afirst embodiment, and FIG. 1B is a schematic cross-sectional view takenalong the line Ib-Ib of FIG. 1A. FIG. 2A is a schematic top view showinga light-emitting device 100A as a modified example of the light-emittingdevice 100, and FIG. 2B is a schematic cross-sectional view taken alongthe line IIb-IIb of FIG. 2A. To easily recognize a blue light-emittingelement 1 b and a green light-emitting element 1 g disposed in alight-transmissive member 3, FIGS. 1A and 2A omit the description of ared phosphor 4.

The light-emitting device 100 has at least one blue light-emittingelement (first light-emitting element) 1 b at an upper surface of afirst lead 36 a disposed at the bottom of a cavity of a resin package 2.The light-emitting device 100 has at least one green light-emittingelement (second light-emitting element) 1 g at an upper surface of asecond lead 36 b disposed at the bottom of the cavity of the resinpackage 2.

That is, the light-emitting device 100 has at least one of each type ofthe blue light-emitting element 1 b and the green light-emitting element1 g. Depending on the target amount of light and the like, thelight-emitting device 100 may include two or more blue light-emittingelements 1 b, and/or two or more green light-emitting elements 1 g. Inthe embodiment shown in FIG. 1A, the number of blue light-emittingelements 1 b is equal to that of the green light-emitting elements 1 g,but the present invention is not limited thereto. Depending on thetarget light-emission properties, the number of blue light-emittingelements 1 b may be greater than that of green light-emitting elements 1g, or the number of green light-emitting elements 1 g may be greaterthan that of blue light-emitting elements 1 b.

The light-emitting device 100A has the blue light-emitting elements 1 band the green light-emitting elements 1 g at the first lead 36 a. In theembodiment shown in FIG. 2A, two blue light-emitting elements 1 b andtwo green light-emitting elements 1 g are disposed at the first lead 36a. The blue light-emitting element 1 b and the green light-emittingelement 1 g are arranged side by side sequentially from the left side ina first row from the bottom edge, while the green light-emitting element1 g and the blue light-emitting element 1 b are arranged side by sidesequentially from the left side in a second row from the bottom edge.Note that in the description below, the light-emitting device 100 willbe mainly described in detail. Elements or components of thelight-emitting devices 100 and 100A represented by the same referencecharacters may have substantially the same structures, except whendescribing specific elements of the light-emitting device 100A.

The blue light-emitting element 1 b has its emission peak wavelength of430 nm or more and less than 490 nm (corresponding to a wavelength rangeof blue light), and preferably 440 nm or more and 470 nm or less. Thegreen light-emitting element 1 g has its emission peak wavelength of 490nm or more and 570 nm of less (corresponding to a wavelength range ofgreen light), and preferably 520 nm or more and 550 nm or less.

Each of the blue light-emitting element 1 b and the green light-emittingelement 1 g is electrically connected, for example, to an externalcircuit including a wiring layer on a mounting substrate, and is adaptedto emit light with power supplied thereto via the external circuit. Inthe embodiment of the light-emitting device 100 as shown in FIGS. 1A and1B, one of the positive and negative electrodes of the bluelight-emitting element 1 b is connected to the first lead 36 a via awire 6; the other electrode of the blue light-emitting element 1 b isconnected to one of the positive and negative electrodes of the greenlight-emitting element 1 g via the wire 6; and the other electrode ofthe green light-emitting element 1 g is connected to the second lead 36b via the wire 6. In the example of the light-emitting device 100 asshown in FIGS. 1A and 1B, the other of the positive and negativeelectrodes of the blue light-emitting element 1 b is connected to one ofthe positive and negative electrodes of the green light-emitting element1 g via the wire 6. However, the present invention is not limited tosuch connection. Alternatively, the other of the positive and negativeelectrodes of the blue light-emitting element 1 b may be connected tothe second lead 36 b via the wire 6, and one of the positive andnegative electrodes of the green light-emitting element 1 g may beconnected to the first lead 36 a via the wire 6. The first lead 36 a isconnected, for example, to the wiring layer on the mounting substrate,while the second lead 36 b is connected, for example, to another wiringlayer on the mounting substrate, whereby the blue light-emitting element1 b and the green light-emitting element 1 g can be electricallyconnected to the external circuit.

In the embodiment of the light-emitting device 100A as shown in FIGS. 2Aand 2B, regarding the blue and green light-emitting elements 1 b and 1 garranged in the first row from the bottom edge, one of the positive andnegative electrodes of the blue light-emitting element 1 b is connectedto the first lead 36 a via a wire 6; the other electrode of the bluelight-emitting element 1 b is connected to one of the positive andnegative electrodes of the green light-emitting element 1 g via the wire6; and the other electrode of the green light-emitting element 1 g isconnected to the second lead 36 b via the wire 6.

On the other hand, in the green light-emitting element 1 g and the bluelight-emitting element 1 b that are arranged in the second row from thebottom edge, one of the positive and negative electrodes of the greenlight-emitting element 1 g is connected to the first lead 36 a via awire 6; the other electrode of the green light-emitting element 1 g isconnected to one of the positive and negative electrodes of the bluelight-emitting element 1 b via the wire 6; and the other electrode ofthe blue light-emitting element 1 b is connected to the second lead 36 bvia the wire 6.

Note that the present invention is not limited to the method whichinvolves directly connecting the electrode of the blue light-emittingelement 1 b to the electrode of the green light-emitting element 1 g viathe wire 6. Like the example of the above-mentioned light-emittingdevice 100, both positive and negative electrodes of the bluelight-emitting element 1 b and the green light-emitting element 1 g maybe connected to the first lead 36 a or second lead 36 b via the wire 6.

Note that in the light-emitting devices 100 and 100A, the resin package2, the first lead 36 a and the second lead 36 b are collectivelyreferred to as a support body 7. The support body as mentioned in thepresent specification is a member for placing the blue light-emittingelement 1 b and the green light-emitting element 1 g. For example, thesupport body includes a base body, such as a resin package or asubstrate, and a conductive member disposed on the surface of or insidethe base body and adapted to supply power to the light-emitting element.Examples of the conductive member can include a lead, a via and a wiringlayer.

The light-transmissive member 3 is disposed in the cavity of the resinpackage 2. The light-transmissive member 3 may be made, for example, ofsealing resin, glass, or the like. The light-transmissive member 3contains the red phosphor 4. The red phosphor 4 absorbs part of bluelight emitted from the blue light-emitting element 1 b to thereby emitred light. That is, the red phosphor 4 converts the wavelength of theblue light to the wavelength of the red light.

The content density of the red phosphor 4 in the space between the bluelight-emitting element 1 b and the green light-emitting element 1 g isset higher in the part below the upper surface of the greenlight-emitting element 1 g than in the part above the upper surface ofthe green light-emitting element 1 g. For example, in the space betweenthe blue light-emitting element 1 b and the green light-emitting element1 g, the content density of the red phosphor 4 in the part below theupper surface of the green light-emitting element 1 g may be two or moretimes as high as that of the red phosphor 4 in the part above the uppersurface of the green light-emitting element 1 g. That is, in the spacebetween the blue and green light-emitting elements 1 b and 1 g, thecontent density of the red phosphor 4 in the part from the upper surfaceof the green light-emitting element 1 g to the lower surface of thelight-transmissive member 3 may be two or more times as high as that ofthe red phosphor 4 in the part from the upper surface of the greenlight-emitting element 1 g to the upper surface of thelight-transmissive member 3.

The expression “the space between the blue light-emitting element 1 band the green light-emitting element 1 g” as used herein contains a partof the light-transmissive member 3 between facing end surfaces of theadjacent blue and green light-emitting elements 1 b and 1 g, as well asa part of the light-transmissive member 3 directly above the aforesaidpart between these end surfaces.

For example, in the embodiments shown in FIGS. 1B and 2B, theabove-mentioned expression means a part between the right end surface ofthe blue light-emitting element 1 b and the left end surface of thegreen light-emitting element 1 b opposed to the right end surface, aswell as a part located above the aforesaid part between these endsurfaces. That is, this expression means the part between the right endsurface of the blue light-emitting element 1 b and the left end surfaceof the green light-emitting element 1 g as viewed in the lateraldirection, and the part above the green light-emitting element 1 g asviewed in the vertical direction. However, as shown in FIG. 2A, in thelight-emitting device 100A, the “space between the blue light-emittingelement 1 b and the green light-emitting element 1 g” additionallycovers a space between the blue and green light-emitting elements 1 band 1 g that are positioned on the left side in the figure, a spacebetween the blue and green light-emitting elements 1 b and 1 g that arepositioned on the upper side of the figure, and a space the blue andgreen light-emitting elements 1 b and 1 g that are positioned on theright side in the figure. When there are such “spaces between the blueand green light-emitting elements 1 b and 1 g”, in at least one space,preferably all “spaces between the blue and green light-emittingelements 1 b and 1 g”, the content density of the red phosphor 4 is sethigher in the part below the upper surface of the green light-emittingelement 1 g than in the part above the upper surface thereof.

The content density of the red phosphor 4 in the light-transmissivemember 3 means the volume of the red phosphor 4 per unit volume of thelight-transmissive member 3. For easier evaluation in terms of practicaluse, the content density of the red phosphor 4 may be determined byobserving the cross section. Specifically, the content density of thered phosphor 4 may be evaluated by an area of the red phosphor 4contained in the unit area of the light-transmissive member 3 in itssection.

A method for controlling the content density (distribution density) ofthe red phosphor 4 mentioned above can be a sedimentation method. In thesedimentation method, for example, the red phosphor is dispersed intothe molten light-transmissive-member forming material, such as moltenresin or glass. For example, after placing the moltenlight-transmissive-member forming material into a part, such as thecavity of the resin package 2, where the light-transmissive member 3 isto be formed, the red phosphor 4 is allowed to settle out by gravity,whereby the content density of the red phosphor 4 in the part below theupper surface of the green light-emitting element 1 g is set higher thanthat in the part above the upper surface thereof. In this state, thelight-transmissive-member forming material is cured, thereby producingthe light-transmissive member 3 having the desired content-densitydistribution of the red phosphor 4. The red phosphor 4 is preferablyforced to settle out using a centrifugal force. For example, beforecuring the light-transmissive-member forming material, thelight-emitting device is centrifugalized by a centrifugal machine,whereby the red phosphor 4 can forcibly settle out.

A preferable embodiment of the content-density distribution of the redphosphor 4 in the light-transmissive member 3 formed by thesedimentation method can be exemplified as shown in FIGS. 1B and 2B.Specifically, in the space between the blue and green light-emittingelements 1 b and 1 g, the red phosphor 4 barely exists near the uppersurface of the light-transmissive member 3, and the distribution densityof the red phosphor 4 is gradually increased downward from the partabove the upper surface of the green light-emitting element 1 g,resulting in the highest distribution density of the red phosphor 4 inthe vicinity of the bottom of the cavity of the resin package 2 (nearthe lower surface of the light-transmissive member 3). To permit the redphosphor 4 to easily settle out in the space between the blue and greenlight-emitting elements 1 b and 1 g at such a height that achieves theeffects of the present invention, the blue light-emitting element 1 band the green light-emitting element 1 g are preferably arranged on thesupport body at a certain interval, for example, with a spacingtherebetween that is larger than the average particle size of the redphosphor. Here, the average particle size of the red phosphor is, interms of volume-average particle size, for example, 1 μm or more and 100μm or less, preferably 5 μm or more and 70 μm or more, and morepreferably 20 μm or more and 70 μm or more. The volume-average particlesize of the red phosphor is a particle size (median size) measured by alaser diffraction particle size analyzer (trade name: MASTERSIZER 2000,manufactured by Malvern Instruments Ltd.).

The red phosphor 4 may include one or more kinds of CASN based and SCASNbased red phosphors.

Preferably, the red phosphor 4 barely absorbs green light in emittingred light. That is, the red phosphor 4 does not substantially convertthe green light to the red light. The reflectance of the red phosphor 4to the green light is preferably 70% or more on average in a wavelengthrange of the green light. The red phosphor 4 is made of a phosphor thathas a high reflectance to the green light, that is, a phosphor thathardly absorbs the green light, or a phosphor that barely converts thewavelength of the green light, which facilitates the design of thelight-emitting device.

The use of a red phosphor that absorbs a large amount of green lightmust consider the wavelength conversion by the red phosphor 4 not onlyfor the light from the blue light-emitting element 1 b, but also for thelight from the green light-emitting element 1 g to balance the outputfrom the light-emitting device. In contrast, like the presentdisclosure, the use of the red phosphor that barely converts thewavelength of the green light only needs to consider the wavelengthconversion of the blue light emitted from the blue light-emittingelement 1 b, thereby enabling the design of the output balance of thelight-emitting device.

Such preferable red phosphors 4 can include the following red phosphors.The red phosphor 4 contains at least one kind of these red phosphors.

A first kind of red phosphor is one with the composition represented bythe following general formula (I):A₂MF₆:Mn⁴⁺  (I)Where, in the above-mentioned general formula (I), A is at least oneselected from the group consisting of K, Li, Na, Rb, Cs and NH⁴⁺; and Mis at least one element selected from the group consisting of Group 4elements and Group 14 elements.

The Group 4 elements are titanium (Ti), zirconium (Zr) and hafnium (Hf).The Group 14 elements are silicon (Si), germanium (Ge), tin (Sn) andlead (Pb).

Specific examples of the first kind of red phosphor can includeK₂SiF₆:Mn⁴⁺, K₂ (Si, Ge) F₆:Mn⁴⁺, and K₂TiF₆:Mn⁴⁺.

The second kind of red phosphor is one with the composition representedby formula of 3.5MgO.0.5MgF₂.GeO₂:Mn⁴⁺, or the composition representedby the following general formula (II):(x−a)MgO.a(Ma)O.b/2(Mb)₂O₃ .yMgF₂ .c(Mc)X₂.(1−d−e)GeO₂ .d(Md)O₂.e(Me)₂O₃:Mn⁴⁺  (II)where, in the above-mentioned general formula (II), Ma is at least oneelement selected from Ca, Sr, Ba and Zn; Mb is at least one elementselected from Sc, La and Lu; Mc is at least one element selected fromCa, Sr, Ba and Zn; X is at least one element selected from F and Cl; Mdis at least one element selected from Ti, Sn and Zr; and Me is at leastone element selected from B, Al, Ga and In. Furthermore, x, y, a, b, c,d and e are set to satisfy the following ranges: 2≤x≤4; 0<y≤2; 0≤a≤1.5;0≤b<1; 0≤c≤2; 0≤d≤0.5; and 0≤e<1.

The red phosphor represented by the above general formula (I) in theabove-mentioned two red phosphors is more preferable than thatrepresented by the above general formula (II) because of the easiness ofexcitation with the light from the blue light-emitting element. The redphosphor represented by the above general formula (I) has its emissionpeak wavelength that is closer to the peak of luminosity curve than thatof the red phosphor represented by the above general formula (II),thereby making it possible to increase the luminous fluxes whilemaintaining red components of the light.

Other specific examples of the second kind of red phosphor can include ared phosphor that has a relatively high reflectance to the green lightand is represented by the following formula: Y₂O₂S:Eu³⁺, La₂O₂S:Eu³⁺,AEu_(x)Ln_((1-x))M₂O₈ (0<X≤1; A is at least one element selected fromLi, Na, K, Pb and Cs; Ln is at least one element selected from Y, La, Cdand Lu; and M is W or Mo).

Such a light-transmissive member 3 covers at least part of the bluelight-emitting element 1 b and at least part of the green light-emittingelement 1 g. The light-transmissive member 3 is disposed to have atleast its part placed in the space between the blue light-emittingelement 1 b and the green light-emitting element 1 g. Preferably, thelight-transmissive member 3 lies over the blue and green light-emittingelements 1 b and 1 g to be in contact with them. As shown in FIGS. 1Aand 1B, the substantially entire surfaces of the blue light-emittingelement 1 b (that is, upper surface and side surfaces thereof), otherthan its bottom surface in contact with the first lead 36 a or secondlead 36 b, may be covered with the light-transmissive member 3.Likewise, the substantially entire surfaces of the green light-emittingelement 1 g (that is, upper surface and side surfaces thereof), otherthan its bottom surface in contact with the first lead 36 a or secondlead 36 b, may be covered with the light-transmissive member 3.

The light-transmissive member 3 covers the blue light-emitting element 1b, whereby part of the blue light emitted from the blue light-emittingelement 1 b is absorbed by the red phosphor 4 in the light-transmissivemember 3, causing the red phosphor 4 to emit the red light therefrom.Then, the blue light not having its wavelength converted by the redphosphor 4 as well as the red light emitted from the red phosphor 4 passthrough the light-transmissive member 3 to be emitted outward from theupper surface of the light-transmissive member 3 (light extractionsurface of the light-emitting device 100). On the other hand, the greenlight emitted from the green light-emitting element 1 g is partlywavelength-converted into the red light by the red phosphor 4(preferably, never converted (or barely converted) into the red light bythe red phosphor 4) to sequentially pass through the light-transmissivemember 3, and then exits outward from the upper surface of thelight-transmissive member 3. In this way, the blue light, the red light,and the green light can be mixed together outside the light-transmissivemember 3 to thereby produce a desired color light, for example, whitelight.

The light-emitting device 100 obtains the green light by the emissionfrom the green light-emitting element 1 g. Thus, the green light caneasily have the sharp peak, compared to a case in which green light isobtained using a green phosphor. As a result, a liquid crystal displayincluding the light-emitting device 100 can achieve the high colorreproducibility.

Further, part of the green light emitted from the green light-emittingelement 1 g is preferably scattered by the red phosphor 4 without havingits wavelength converted. In this case, the intensity distribution ofthe green light outside the light-transmissive member 3 becomes uniform,thereby enabling the suppression of occurrence of color unevenness.Moreover, for example, the light-transmissive member 3 is used as asealing resin, and the resin covering the blue light-emitting element 1b and the resin covering the green light-emitting element 1 g aredesigned to be made of the same light-transmissive member 3, which isadvantageous in terms of the productivity.

Elements forming the light-emitting device 100 will be described indetail below.

Light-Emitting Element

The blue light-emitting element 1 b and the green light-emitting element1 g may be arranged in any form. Preferable arrangement of them will beexemplified below.

As shown in FIGS. 1A and 1B, the longitudinal directions of the bluelight-emitting element 1 b and the green light-emitting element 1 g maybe set in parallel with the longitudinal direction of the support body 7(in the lateral direction shown in FIGS. 1A and 1B). Additionally oralternatively, as illustrated in FIGS. 1A and 1B, the longitudinaldirection of the blue light-emitting element 1 b and the longitudinaldirection of the green light-emitting element 1 g should be aligned onone straight line. Thus, the light emitted from the light-emittingelements can be more uniformly dispersed across the entirelight-emitting device 100.

The longitudinal direction of each of the blue light-emitting element 1b and the green light-emitting element 1 g may be set in parallel withthe longitudinal direction of a light-emitting element mounting surfaceof the support body 7. Here, the light-emitting element mounting surfaceof the support body 7 is a surface of the support body 7 over which atleast one of the blue light-emitting element 1 b and the greenlight-emitting element 1 g is mounted.

When using a plurality of blue light-emitting elements 1 b and aplurality of green light-emitting elements 1 g, like the light-emittingdevice 100A, as shown in FIG. 2A, the blue and green light-emittingelements 1 b and 1 g may be disposed alternately. That is, thelight-emitting element closest to the blue light-emitting element 1 b(for example, the light-emitting element with the shortest distancebetween the center portions of these light-emitting elements) is thegreen light-emitting element 1 g, while the light-emitting elementclosest to the green light-emitting element 1 g is the bluelight-emitting element 1 b. With this arrangement, the occurrence ofcolor unevenness can be suppressed.

As shown in FIG. 2A, the blue light-emitting element 1 b and the greenlight-emitting element 1 g are arranged in one row so as to have theirlongitudinal directions aligned with one straight line, and a pluralityof such rows may be That is, preferably, the longitudinal direction ofthe blue light-emitting element 1 b and the longitudinal direction ofthe green light-emitting element 1 g may be arranged on one straightline, and the longitudinal direction of another blue light-emittingelement 1 b and the longitudinal direction of another greenlight-emitting element 1 g may be arranged on another straight line.

The preferable arrangements mentioned above may be combined together.

The blue light-emitting element 1 b and the green light-emitting element1 g may be semiconductor elements, such as a light-emitting diode (LED)that spontaneously emits the lights by applying a voltage. Thesemiconductor suitable for use in the blue light-emitting element 1 band the green light-emitting element 1 g can be a nitride-basedsemiconductor (In_(X)Al_(Y)Ga_(1-x-y)N, 0≤X, 0≤Y, X+Y≤1), or the like.That is, the blue light-emitting element 1 b and the greenlight-emitting element 1 g may be nitride semiconductor elements. Inthis way, the semiconductor materials for the different light-emittingelements are set to the same kind of the nitride-based semiconductor, sothat a voltage in the forward direction (forward voltage) Vf of thelight-emitting element is made the same between the differentlight-emitting elements, which preferably eliminates the necessity ofindividually setting the conditions for driving the light-emittingelements. The number of blue light-emitting elements 1 b disposed at thesupport body 7 may be singular or plural, and the number of greenlight-emitting elements 1 g disposed at the support body 7 may also besingular or plural. The planar shape of each of the blue light-emittingelement 1 b and the green light-emitting element 1 g may be square orrectangular. Alternatively, the blue light-emitting element 1 b and thegreen light-emitting element 1 g may be combined together, and aplurality of combinations may be arranged. The number or shape oflight-emitting elements can be selected as appropriate, depending on theshape or size of the support body 7.

The light output from the blue light-emitting element 1 b may be thesame as that from the green light-emitting element 1 g. Depending on thetarget properties, such as color reproducibility, the light output fromthe blue light-emitting element 1 b may differ from that from the greenlight-emitting element 1 g. In one embodiment that can achieve theexcellent color reproducibility, the ratio of the light output from thegreen light-emitting element 1 g to that from the blue light-emittingelement 1 b may be set at 0.3 or more and 0.7 or less.

The ratio of the light output between the light-emitting elements can bedetermined by measuring respective emission spectra by aspectrophotometer, and then calculating the ratio of the emission peakheight of the green light-emitting element to that of the bluelight-emitting element.

Although in the embodiment shown in FIGS. 1B and 2B, the upper surfaceof the blue light-emitting element 1 b is positioned at the same heightas the upper surface of the green light-emitting element 1 g, thepresent invention is not limited thereto. Alternatively, the uppersurface of the green light-emitting element 1 g may be positioned abovethe upper surface of the blue light-emitting element 1 b. That is, theupper surface of the green light-emitting element 1 g may be disposedcloser to the light extraction surface of the light-emitting device 100(upper surface of the light-transmissive member 3) than the uppersurface of the blue light-emitting element 1 b is. For example, thegreen light-emitting element 1 g is disposed on a sub-mount member andthen placed on the support body such that its upper surface is locatedat the higher level than the upper surface of the blue light-emittingelement 1 b. Alternatively or additionally, a stepped portion is formedat the element arrangement surface of the support body for the greenlight-emitting element 1 g or blue light-emitting element 1 b. Further,these methods can be combined in use. With such an arrangement, forexample, the excellent color reproducibility can be obtained even whenthe light output from the green light-emitting element 1 g is lower thanthat from the blue light-emitting element 1 b to some extent.

Light-Transmissive Member

The light-transmissive member 3 may be formed of any material, such asresin or glass. When forming the light-transmissive member 3 usingresin, any resin may be used. A preferable example of material for thelight-transmissive member is transparent resin. This is because theabsorption of lights emitted from the blue and green light-emittingelements 1 b and 1 g and from the red phosphor 4 can be suppressed.Another preferable example is a semitransparent resin that contains adiffusing agent, such as TiO₂ or SiO₂, in a transparent resin. This isbecause the lights emitted from the blue and green light-emittingelements 1 b and 1 g and from the red phosphor 4 are suppressed frombeing absorbed to some degree, and these lights can be diffusedsufficiently.

Such preferable resins can include, for example, silicone-based resin,and epoxy-based resin. This kind of resin is molten and mixed with thered phosphor 4, causing the red phosphor 4 to be dispersed in the resin.The resin with the red phosphor 4 dispersed therein is charged into thecavity of the resin package 2 and then cured, thereby enabling theformation of the light-transmissive member 3.

Resin Package

The resin package 2 may be formed of any resin.

Preferable resins can include, for example, a nylon-based resin, anepoxy-based resin and a silicone-based resin.

For example, a reflective material, such as a metal plating made ofsilver (Ag) or the like, may be disposed at the surface of the cavity inthe resin package 2. Alternatively, the color of the surface of thecavity may be white and the like. Thus, the light reflectance of thesurface of the cavity can be improved, permitting a large amount oflight reaching the cavity surface to reflect in the emission direction,thus enhancing the efficiency of the light-emitting device 100.

Alternatively, instead of the resin package with the cavity, forexample, an insulating substrate is made of ceramic, resin, dielectricmaterial, glass, or a composite material thereof, and connectionterminals are disposed on a surface of the insulating substrate, wherebya support body can also be produced. Further, the blue light-emittingelement 1 b and the green light-emitting element 1 g may be disposed atthe support body, and the light-transmissive member 3 containing the redphosphor 4 may be formed, for example, by molding to cover the bluelight-emitting element 1 b and the green light-emitting element 1 g.

The light-emitting device 100 may be manufactured by a manufacturingmethod below.

After disposing the first lead 36 a and the second lead 36 b in a mold,the resin is charged into the mold, thereby integrally forming the resinpackage 2, the first lead 36 a and the second lead 36 b. The bluelight-emitting element 1 b is arranged on a part of the first lead 36 aexposed from the bottom surface of the cavity of the resin package 2.The green light-emitting element 1 g is arranged on a part of the secondlead 36 b exposed from the bottom surface of the cavity of the resinpackage 2. Thereafter, the wires 6 are used to connect between the lead36 a and the blue light-emitting element 1 b, between the bluelight-emitting element 1 b and the green light-emitting element 1 g, andbetween the green light-emitting element 1 g and the second lead 36 b,respectively.

Then, the molten resin containing the red phosphor 4 is charged into thecavity of the resin package 2 to be in contact with at least parts ofthe blue and green light-emitting elements 1 b and 1 g, allowing the redphosphor 4 to settle out, followed by curing the resin, therebyproducing the light-transmissive member 3.

The light-emitting device 100 mentioned above is called “a top viewlight-emitting device” that has its upper surface as the lightextraction surface and its lower surface as the mounting surface.However, the light-emitting device according to the present disclosureis not limited thereto, and encompasses the so-called side viewlight-emitting device that has its surface adjacent to the lightextraction surface as a mounting surface and emits light in thedirection parallel to the mounting surface.

2. Second Embodiment

FIG. 3 is a schematic top view showing a backlight 200 according to asecond embodiment. The backlight 200 includes the light-emitting device100 as mentioned below. However, the light-emitting device 100 for usein the description below may be replaced by the light-emitting device100A.

The backlight 200 includes a case 20, a light guide plate 22 disposed inthe case 20, and the light-emitting device 100 disposed in the case 20and adapted to emit the light toward the light guide plate 22. Thebacklight 200 irradiates a desired device, such as a liquid crystalpanel, with light from the light-emitting device 100 via the light guideplate 22.

The case 20 may be formed to make its inner surface reflective. Forexample, its inner surface may be colored in white.

At least one of four side surfaces of the light guide plate 22 is usedas an incident surface (light input portion). In the embodiment shown inFIG. 3, the side surface positioned on the lower side serves as theincident surface. The light-emitting device 100 is disposed such thatits light extraction surface faces the incident surface. Preferably, aplurality of light-emitting devices 100 is disposed along the incidentsurface. The light emitted from the light-emitting device 100 enters theinside of the light guide plate 22 from the incident surface. When usingthe plurality of light-emitting devices 100, the lights emitted from thedifferent light-emitting devices 100 are mixed in the light guide plate22.

The upper surface of the light guide plate 22 serves as an emissionsurface. A desired device, such as the liquid crystal panel, is disposedat the emission surface, thus allowing the light from the light guideplate 22 to be directed toward such a device.

The light extraction surface of the light-emitting device 100 and thelight input portion (incident surface) of the light guide plate 22 maybe disposed to keep their longitudinal directions aligned. Thelongitudinal direction of the light extraction surface of thelight-emitting device 100 is set in parallel to the longitudinaldirection of the light input surface of the light guide plate, therebyenabling the light from the light-emitting device 100 to be moreefficiently guided into the light guide plate 22.

EXAMPLES 1. Example 1

As a light-emitting device in Example 1, the above-mentionedlight-emitting device 100 was used. In the light-emitting device 100,one blue light-emitting element 1 b and one green light-emitting element1 g were respectively disposed in parallel with the long-side directionof the support body 7 (the long-side direction of a light-emittingelement mounting surface of the support body). As the red phosphor 4,K₂SiF₆:Mn⁴⁺ was used. The red phosphor 4 settled out in the spacebetween the blue light-emitting element 1 b and the green light-emittingelement 1 g by the sedimentation method such that the content density ofthe red phosphor 4 is higher in the part below the upper surface of thegreen light-emitting element 1 g than in the part above the uppersurface of the green light-emitting element 1 g. With this arrangement,most of the blue light directed from the blue light-emitting element 1 bto the green light-emitting element 1 g is converted into the red lightby the red phosphor, thereby reducing the light absorption between theblue light emitting elements 1 b and the green light emitting elements 1g.

In a light-emitting device used in Comparative Example 1, the greenlight-emitting element 1 g of the light-emitting device 100 was replacedby the blue light-emitting element 1 b, whereby the two bluelight-emitting elements 1 b in total were used. Further, thelight-transmissive member 3 used β-sialon as a green phosphor, inaddition to the red phosphor 4. Specifically, the resin and red phosphorin the same amounts as in Example 1, to which the green phosphor wasadded, were prepared as the light-transmissive-member forming material,whereby the light-transmissive member 3 was produced.

FIG. 4 shows an emission spectrum from the light-emitting device 100 inExample 1, and FIG. 5 shows an emission spectrum from the light-emittingdevice in Comparative Example 1. The light-emitting device in Example 1and the light-emitting device in Comparative Example 1 were used thatwere designed to obtain as similar white points (chromaticity points ofW) as possible after the respective lights passed through color filtersmentioned below.

The color filters were attached to the light-emitting devices of Example1 and Comparative Example 1, and the light from each light-emittingdevice was allowed to pass through the color filter. In more detail,Example 1 and Comparative Example 1 employed a liquid crystal panelusing the color filters designed to create a wide color gamut after thetransmission of light through the color filters. FIG. 6 shows atransmission spectrum of the employed color filters.

Table 1 shows chromaticity points of the light-emitting devices obtainedbefore and after the light passed through the color filters. It is foundthat the chromaticity points of the light-emitting device in Example 1are similar to those of the light-emitting device in Comparative Example1.

TABLE 1 Comparative Example 1 Example 1 x y x y Before transmission LED0.291 0.322 0.294 0.319 through color filters After transmission B 0.1500.055 0.148 0.057 through color filters G 0.191 0.730 0.206 0.708 R0.684 0.304 0.678 0.310 W 0.297 0.313 0.294 0.306

Table 2 shows the ratio of the brightness between before and after thelight passed through the color filters. Before the light passed throughthe color filters, the brightness of the light-emitting device inComparative Example 1 was higher than that in Example 1. In contrast,after the light passed through the color filters, the brightness of thelight-emitting device in Example 1 was substantially equal to that inComparative Example 1. This result shows that the light emitted from thelight-emitting device in Comparative Example 1 was absorbed by the colorfilters more than the light emitted from the light-emitting device inExample 1 when passing through the color filters. That is, it revealsthat the light emitted from the light-emitting device in Example 1passed through the color filter with higher efficiency than that inComparative Example 1.

TABLE 2 Comparative Example 1 Example 1 Before transmission Brightness 11.041 through color filters [a.u.] After transmission Brightness 1 1.000through color filters [a.u.]

Table 3 shows an area ratio and a coverage of each color gamut standardfor the light having passed through the color filters. FIG. 7 shows thegraph of the results. Because of the use of the liquid crystal panelwith the color filters creating the wide color gamut, even thelight-emitting device in Comparative Example 1 exhibited almost 100%coverage of Adobe RGB standard, which was substantially the same levelas that in the use of the light-emitting device in Example 1.

However, by comparison based on BT2020 standard, which has a wider colorgamut than that of Adobe RGB, the light-emitting device used in Example1 showed 82.6% coverage, while the light-emitting device used inComparative Example 1 showed 77.9% coverage. Thus, Example 1 improvedthe coverage by 4.7 percent points, compared to Comparative Example 1.As can be seen from this result, in use of the wide color gamut panel,the light-emitting device used in Example 1 can cover the wider colorgamut while keeping the panel brightness, compared to the light-emittingdevice used in Comparative Example 1. FIG. 7 also shows that in thelight-emitting device used in Example 1, a green chromaticity point ismoved to the deeper side to thereby enlarge the coverage in the BT2020standard, compared to the light-emitting device used in ComparativeExample 1.

TABLE 3 Comparative Example 1 Example 1 After NTSC ratio [%] 110.6 104.4transmission NTSC coverage [%] 97.6 95.8 through Adobe RGB ratio [%]115.8 109.3 color filters Adobe RGB coverage [%] 100 99.7 (x, y) BT2020ratio [%] 82.6 77.9 BT2020 coverage [%] 82.6 77.9

2. Example 2

A light-emitting device having the same structure as that of Example 1was used in Example 2, while a light-emitting device having the samestructure as that of Comparative Example 1 was used in ComparativeExample 2. The light-emitting device in Example 2 and the light-emittingdevice in Comparative Example 2 were used that were designed to obtainas similar white points (W chromaticity points) as possible after therespective lights passed through the color filters mentioned below.

The color filters were attached to the respective light-emitting devicesof Example 2 and Comparative Example 2, and the light from eachlight-emitting device was allowed to pass through the color filters.

In more detail, Example 1 and Comparative Example 1 employed a liquidcrystal panel using the color filters, which were designed to allow acolor gamut to achieve a high coverage in sRGB standard after thetransmission through the color filters when using a light-emittingdevice including a combination of a blue light-emitting element and aYAG phosphor commonly used for backlights. FIG. 8 shows a transmissionspectrum of the employed color filters.

Table 4 shows chromaticity points of the light-emitting device obtainedbefore and after the light passed through the color filters. It is foundthat the chromaticity points of the light-emitting device in Example 2are similar to those of the light-emitting device in Comparative Example2.

TABLE 4 Comparative Example 2 Example 2 x y x y Before transmission LED0.291 0.322 0.294 0.319 through color filters After transmission B 0.1530.061 0.151 0.063 through color filters G 0.213 0.723 0.237 0.696 R0.684 0.304 0.678 0.310 W 0.315 0.375 0.316 0.370

Table 5 shows the ratio of the radiant flux and brightness betweenbefore and after the light passed through the color filters. Before thelight passed through the color filters, the brightness of thelight-emitting device in Comparative Example 2 was higher than that inExample 2. Even after the light passed through the color filters, thebrightness of the light-emitting device in Comparative Example 2 washigher than that in Example 2, but a difference in brightnesstherebetween was smaller than that before the light passed through thecolor filters. This result shows that the light emitted from thelight-emitting device in Comparative Example 2 was absorbed by the colorfilters more than the light emitted from the light-emitting device inExample 2 when passing through the color filter. That is, the lightemission from the light-emitting device in Example 2 passed through thecolor filters with higher efficiency than that in Comparative Example 2.

TABLE 5 Comparative Example 2 Example 2 Before transmission Brightness 11.041 through color filters [a.u.] After transmission Brightness 1 1.019through color filters [a.u.]

Table 6 shows an area ratio and a coverage of each color gamut standardfor the light having passed through the color filters. Because of theuse of the liquid crystal panel with the color filters designed to havethe high coverage in the sRGB standard, even the light-emitting devicein Comparative Example 2 exhibited almost 100% coverage of sRGBstandard, which was substantially the same level as that in the use ofthe light-emitting device in Example 2.

However, as shown in FIG. 8, when using color filters with a lowertransmittance for each color in which a green color filter exhibited awider full width at half maximum of the transmission spectrum, ascompared to Example 1, the light-emitting device in Comparative Example2 attained a coverage of 93.7% in terms of Adobe RGB standard which hada wider color gamut than sRGB, while the light-emitting device inExample 2 attained a coverage of 99.0%, which could cover almost thewhole color gamut in the Adobe RGB standard. The light-emitting deviceused in Example 2 improved the coverage by 5.3 percent points, comparedto the light-emitting device used in Comparative Example 2. As can beseen from this result, in using the liquid crystal panel with the sRGBstandard color filter, the light-emitting device used in Example 2slightly degrades the panel brightness, compared to the light-emittingdevice used in Comparative Example 2, but the light-emitting device inExample 2 can drastically improve the coverage of the Adobe RGBstandard, compared to Comparative Example 2. As can be seen from FIG. 9,when using the light-emitting device of Example 2, the greenchromaticity point is positioned to the deeper side to thereby enlargethe coverage in the Adobe RGB standard, compared to the light-emittingdevice in Comparative Example 2.

TABLE 6 Comparative Example 2 Example 2 After NTSC ratio [%] 106.4 98.6transmission NTSC coverage [%] 95.8 90.6 through Adobe RGB ratio [%]111.4 103.2 color filters Adobe RGB coverage [%] 99.0 93.7 (x, y) BT2020ratio [%] 79.5 73.6 BT2020 coverage [%] 79.5 73.6 sRGB ratio [%] 150.2139.1 sRGB coverage [%] 100 100

The light-emitting device according to the present disclosure can beused, for example, as backlights for liquid crystal displays.

What is claimed is:
 1. A light-emitting device, comprising: a firstlight-emitting element having an emission peak wavelength of 430 nm ormore and less than 490 nm; a second light-emitting element having anemission peak wavelength of 490 nm or more and 570 nm or less; a supportbody containing a first lead at which the first light-emitting elementis disposed, a second lead at which the second light-emitting element isdisposed, and a resin package located in a space between the first leadand the second lead; and a light-transmissive member containing redphosphor particles and covering the first light-emitting element and thesecond light-emitting element, wherein an upper surface of the firstlead, an upper surface of the second lead and an upper surface of theresin package are positioned on the same plane, and a lower surface ofthe first lead, a lower surface of the second lead and a lower surfaceof the resin package are positioned on the same plane, wherein one ofthe red phosphor particles is located in a top end of an interfacebetween the first lead and the resin package, and another of the redphosphor particles is located in a top end of an interface between thesecond lead and the resin package, wherein a content density of the redphosphor particles in the light-transmissive member located in a spacebetween the first light-emitting element and the second light-emittingelement is higher in apart below an upper surface of the secondlight-emitting element than in a part above the upper surface thereof,and the red phosphor particles located in the light-transmissive memberin the space between the first light-emitting element and the secondlight-emitting element settle out so as to be in contact with eachother, wherein the red phosphor particles include one or more of aphosphor with the composition represented by 3.5MgO.0.5MgF₂.GeO₂:Mn⁴⁺,and a fluoride phosphor, wherein the fluoride phosphor has a compositionincluding one or more selected from the group consisting of K, Li, Na,Rb, Cs and NH⁴⁺; one or more elements selected from the group consistingof Group 4 elements and Group 14 elements; and tetravalent Mn.
 2. Thelight-emitting device according to claim 1, wherein the firstlight-emitting element and the second light-emitting element arealternately arranged in a longitudinal direction and a lateral directionat an element mounting surface of the support body.
 3. Thelight-emitting device according to claim 1, wherein a ratio of a lightoutput from the second light-emitting element to that from the firstlight-emitting element is in a range of 0.3 or more and 0.7 or less. 4.The light-emitting device according to claim 1, wherein an upper surfaceof the second light-emitting element is positioned closer to a lightextraction surface of the light-emitting device, compared to an uppersurface of the first light-emitting element.
 5. The light-emittingdevice according to claim 1, wherein the first light-emitting elementand the second light-emitting element are nitride semiconductorlight-emitting elements.
 6. The light-emitting device according to claim1, wherein one of positive and negative electrodes of the firstlight-emitting element is connected to one of positive and negativeelectrodes of the second light-emitting element via a wire.
 7. Abacklight comprising: the light-emitting device according to claim 1;and a light guide plate having a light input portion at a side surfacethereof, wherein a light extraction surface of the light-emitting deviceand the light input portion are disposed facing each other.
 8. Thelight-emitting device according to claim 1, wherein the red phosphorparticles in the light-transmissive member located in the space betweenthe first light-emitting element and the second light-emitting elementcontinuously contact the support body, a lateral surface of the firstlight-emitting element, and a lateral surface of the secondlight-emitting element.
 9. The light-emitting device according to claim1, wherein the content density of the red phosphor particles isgradually increased downward from the part above the upper surface ofthe second light-emitting element.
 10. The light-emitting deviceaccording to claim 9, wherein the content density of the red phosphorparticles is highest in the vicinity of the support body.
 11. Thelight-emitting device according to claim 1, wherein a volume-averageparticle size of the red phosphor particles is in range of 1 μm or moreand 100 μm or less.
 12. The light-emitting device according to claim 1,wherein a reflectance of the red phosphor particles to the light fromthe second light-emitting element is 70% or more.
 13. The light-emittingdevice according to claim 1, wherein the red phosphor particles includea phosphor selected from the group consisting of Y₂O₂S:Eu³⁺,La₂O₂S:Eu³⁺, and AEu_(X)Ln_((1-X))M₂O₈, wherein 0<X≤1; A is at least oneelement selected from Li, Na, K, Pb and Cs; Ln is at least one elementselected from Y, La, Cd and Lu; and M is W or Mo.
 14. The light-emittingdevice according to claim 1, wherein the red phosphor particles includea phosphor selected from the group consisting of K₂SiF₆:Mn⁴⁺, K₂ (Si,Ge)F₆:Mn⁴⁺ and K₂TiF₆:Mn⁴⁺.
 15. The light-emitting device according toclaim 1, wherein the red phosphor particles include a phosphor having acomposition represented by the following formula (II):(x−a)MgO.a(Ma)O.b/2(Mb)₂O₃ .yMgF₂ .c(Mc)X₂.(1-d-e)GeO₂ .d(Md)O₂.e(Me)₂O₃:Mn⁴⁺  (II) wherein Ma is at least one element selected fromCa, Sr, Ba and Zn; Mb is at least one element selected from Sc, La andLu; Mc is at least one element selected from Ca, Sr, Ba and Zn; X is atleast one element selected from F and Cl; Md is at least one elementselected from Ti, Sn and Zr; and Me is at least one element selectedfrom B, Al, Ga and In; wherein x, y, a, b, c, d and e are set to satisfythe following ranges: 2≤x≤4; 0<y≤2; 0≤a≤1.5; 0≤b<1; 0≤c≤2; 0≤d≤0.5; and0≤e<1.
 16. The light-emitting device according to claim 1, wherein inthe space between the first light-emitting element and the secondlight-emitting element, the content density of the red phosphorparticles from the upper surface of the second light-emitting element toa lower surface of the light-transmissive member is two or more times ashigh as that of the red phosphor particles in the part from the uppersurface of the second light-emitting element to an upper surface of thelight-transmissive member.
 17. The light-emitting device according toclaim 1, wherein the light-transmissive member contains a diffusingagent.
 18. The light-emitting device according to claim 17, wherein thediffusing agent is TiO₂ or SiO₂.
 19. The light-emitting device accordingto claim 1, wherein the Group 4 elements are titanium (Ti), zirconium(Zr) and hafnium (Hf), and the Group 14 elements are silicon (Si),germanium (Ge), tin (Sn) and lead (Pb).
 20. The light-emitting deviceaccording to claim 1, wherein the fluoride phosphor is one with thecomposition represented by the general formula (I):A₂MF₆:Mn⁴⁺  (I) where, in the general formula (I), A is one or moreselected from the group consisting of K, Li, Na, Rb, Cs and NH⁴⁺; and Mis one or more elements selected from the group consisting of Group 4elements and Group 14 elements.